We cleat the rudders in the horizontal position, than loop the "Tee" handle around the rudder tube and thru itself as a failsafe to keep the rope engaged in the Vee cleat.

A bungee from each rudder stem to the furthest you can stretch them inwards, hooked to the tramp rear lace, keeps them from flopping about.

One thing.. put a 1" long piece of hose over the pull up rope just above the rudder head where it ties to it. (a la Nacra "up" bungee) to stop a bump slaming the rudder head into the pulley washers which dink it up.

Ihad set my p18 mast saddle with an additional "u" shaped cutout so as to lay the tiller extension in it and along the stowed mast-so securing it and the rudders/crossbar from flopping about. Email me if you like - I may even have a template for the rigamarole. Slick, quick and secure.